From: Peter Zijlstra <peterz@infradead.org>
To: Valentin Schneider <valentin.schneider@arm.com>
Cc: "Barry Song" <21cnbao@gmail.com>,
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Subject: Re: [PATCH 2/2] sched: Centralize SCHED_{SMT, MC, CLUSTER} definitions
Date: Fri, 15 Oct 2021 15:04:50 +0200 [thread overview]
Message-ID: <YWl8cogsS2Lah1mk@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <87bl3zlex8.mognet@arm.com>
On Fri, Oct 08, 2021 at 04:22:27PM +0100, Valentin Schneider wrote:
> So x86 has it default yes, and a lot of others (e.g. arm64) have it default
> no.
>
> IMO you don't gain much by disabling them. SCHED_MC and SCHED_CLUSTER only
> control the presence of a sched_domain_topology_level - if it's useless it
> gets degenerated at domain build time. Some valid reasons for not using
> them is if the architecture defines its own topology table (e.g. powerpc
> has CACHE and MC levels which are not gated behind any CONFIG).
>
> SCHED_SMT has an impact on code generated in sched/core.c, but that is also
> gated by a static key.
>
> So I'd say having them default yes is sensible. I'd even say we should
> change the "If unsure say N here." to "Y".
Right, so I tend to agree (and also that we should fix that Kconfig help
text). But it would be very nice to have feedback from the affected arch
maintainers.
prev parent reply other threads:[~2021-10-15 13:06 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-08 11:53 [PATCH 0/2] sched: cleanup CONFIG_SCHED_MC & friends Valentin Schneider
2021-10-08 11:53 ` [PATCH 1/2] sched: Move Kconfig.preempt to sched/Kconfig Valentin Schneider
2021-10-08 11:53 ` [PATCH 2/2] sched: Centralize SCHED_{SMT, MC, CLUSTER} definitions Valentin Schneider
2021-10-08 12:37 ` Barry Song
2021-10-08 15:22 ` Valentin Schneider
2021-10-15 13:04 ` Peter Zijlstra [this message]
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